Julian Jaynes (February 27, 1920 - November 21, 1997) was an American psychologist, best known for his book The Origin of Consciousness in the Breakdown of the Bicameral Mind (1976), in which he argued that ancient peoples were not conscious (did not possess an introspective mind-space), but instead had their behavior directed by auditory hallucinations, which they interpreted as the voice of their chief, king, or the gods. Jaynes argued that the change from this mode of thinking (which he called the bicameral mind) to consciousness occurred over a period of centuries about three thousand years ago and was based on the development of metaphorical language and the emergence of writing